libdmtx-mobile

Port of libdmtx and libdmtx-wrappers for Java and Cocoa to Android and iOS respectively.

How to use

Android

import org.libdmtx.DMTXImage

val bitmap = //.. obtain android.graphics.Bitmap in ARGB_8888 format from Camera or Gallery

// retrieve raw image data to DMTXImage
val dmtxImage = run {
  val dmtxBufferArray = IntArray(bitmap.width * bitmap.height)
  bitmap.getPixels(dmtxBufferArray, 0, bitmap.width, 0, 0, bitmap.width, bitmap.height)
  DMTXImage(bitmap.width, bitmap.height, dmtxBufferArray)
}
// find 1 data matrix tag with 2000ms timeout
val tags = dmtxImage.getTags(1, 2000)
if (tags.isEmpty()) {
  // no data matrix found
} else {
  // retrieve output result
  val result = tags.first().id
}

iOS

import libdmtx

let image = //... obtain an UIImage from Camera or Gallery in ARGB8 format

let result = (SHDataMatrixReader.sharedDataMatrixReader() as! SHDataMatrixReader).decodeBarcode(from: image)

// result is non-empty NSString, nil if decoding is unsuccessfull

Building

Android

Requirements

• Bazel 5.2.0 or newer.
• Android SDK and environment variable ANDROID_HOME set to its path if not set.
• Android SDK build tools 30.0.3.
• Android NDK 21.4.7075529 and environment variable ANDROID_NDK_HOME set to its path.

Building artifacts

Build AAR containing all binaries with:

bazel build -c opt --strip=ALWAYS \
    --host_crosstool_top=@bazel_tools//tools/cpp:toolchain \
    --fat_apk_cpu=arm64-v8a,armeabi-v7a,x86,x86_64 \
    --legacy_whole_archive=0 \
    --features=-legacy_whole_archive \
    --copt=-fvisibility=hidden \
    --copt=-ffunction-sections \
    --copt=-fdata-sections \
    --copt=-fstack-protector \
    --copt=-Oz \
    --copt=-fomit-frame-pointer \
    --copt=-DABSL_MIN_LOG_LEVEL=2 \
    --linkopt=-Wl,--gc-sections,--strip-all \
    //libdmtx-android:libdmtx-android

Resulting AAR should be in bazel-bin/libdmtx-android/libdmtx-android.aar. JNI .so binaries are inside AAR's jni folder. These files are single shared libraries with libdmtx and the JNI wrapper.

Individual .so files for dynamic loading without JNI wrapper can be build with:

bazel build //thirdparty:libdmtx --config=android_arm

Acceptable values for --config are android_arm, android_arm64, android_x86, android_x86_64. Resulting .so will be in bazel-bin/external/libdmtx folder.

iOS

Requirements

• Bazel 5.2.0 or newer
• Xcode command line tools
• You might need to comment the Android SDK/NDK lines in the WORKSPACE file.

Building artifacts

Build the single libdmtx static frameworks with the following commands:

bazel build -c opt //libdmtx-ios:libdmtx --config=ios_arm64 // phone
bazel build -c opt //libdmtx-ios:libdmtx --config=ios_x86_64 // simulator
bazel build -c opt //libdmtx-ios:libdmtx --config=ios_sim_arm64 // arm64 simulator

• Acceptable values for --config are ios_armv7, ios_arm64, ios_i386, ios_x86_64, ios_sim_arm64, ios_sim_universal (both x86_64 and sim_arm64).
• The resulting .framework can be extracted from the libdmtx.zip file located at the respective bazel-out/applebin_ios-ios_<arch>*/bin/libdmtx-ios/ path.

Build .xcframework with the following script. It will first build individual frameworks for arm64 and combined sim_arm64 and x86_64 targets and then package them to XCframework. Output libdmtx.xcframework will be in the root folder.

./scripts/buildXCFramework.sh